This invention relates to a vacuum system for a fuel stabilization unit (FSU) for a gas turbine engine. More particularly, this invention relates to an ejector-driven system for generating a vacuum utilized in removing dissolved oxygen from a fuel stream.
A fuel stabilization unit (FSU) reduces the amount of oxygen dissolved within fuel for a gas turbine engine. Reducing the amount of oxygen in a fuel increases the maximum allowable temperature of the fuel, thereby increasing its heat sink capacity when used for cooling components onboard the aircraft. One method of removing dissolved oxygen from fuels is by using a semi-permeable membrane deoxygenator. In a membrane deoxygenator, fuel is pumped over an oxygen permeable membrane. As the fuel passes over the membrane, a partial oxygen pressure differential across the membrane promotes the transport of oxygen out of the fuel through the membrane.
A vacuum is one means of generating the required partial oxygen pressure differential. Typically, multi-stage vacuums are created using vacuum pumps. Each vacuum pump is sized according to the volume of waste flow that passes through the vacuum pump. The volume of waste flow is dependant on the amount of deoxygenation required for the system. As the size of vacuum pumps increase so does the cost and overall weight of the system. As can be appreciated, space aboard an aircraft is limited and any increase in device size affects overall configuration and operation.